Low interference cellular data commnunication in unlicensed frequency spectrum

Abstract

A cellular base station communicates data using both the licensed and unlicensed frequency spectrums. For each interval of a set of intervals (such as intervals corresponding to communication of LTE frames), the base station first identifies whether signaling is detected on a specified unlicensed frequency channel (UFC). If a signal is detected, the base station communicates data only over a licensed frequency channel (LFC) for the interval, and does not employ the UFC for the interval. If no signal is detected, the base station communicates data over the interval on both the LFC and the UFC. To ensure that other devices have the opportunity to use the UFC in a timely fashion, the base station communicates data over the UFC for only a portion of the interval.

What is claimed is: 
     
         1 . A method comprising:
 in response to determining at the cellular base station that an unlicensed frequency channel is available for data communication:
 generating a first frame of data including a first portion of the first data targeted to user equipment; 
 communicating the first frame of data via a licensed frequency channel for a first interval; 
 communicating a second portion of the first data via the unlicensed frequency channel for a first subinterval of the first interval; and 
 subsequently suspending communication of data via the unlicensed frequency channel for a blank subinterval of the first interval. 
   
     
     
         2 . The method of  claim 1 , further comprising:
 in response to determining at the cellular base station that the unlicensed frequency channel is not available for data communication, communicating the first frame of data via the licensed frequency channel for the first interval and suspending communication of data via the unlicensed frequency channel during the first interval.   
     
     
         3 . The method of  claim 1 , further comprising:
 setting a length of the blank subinterval in response to detecting a signal on the unlicensed frequency channel.   
     
     
         4 . The method of  claim 3 , wherein setting the length of the blank subinterval comprises increasing the length of the blank subinterval in response to not detecting a signal on the unlicensed frequency channel. 
     
     
         5 . The method of  claim 3 , wherein setting of the length of the blank subinterval comprises decreasing the length of the blank subinterval in response to detecting a signal on the unlicensed frequency channel. 
     
     
         6 . The method of  claim 1 , further comprising:
 after communicating the first frame of data, sensing one or more signals on the unlicensed frequency channel to determine an availability of the unlicensed frequency channel.   
     
     
         7 . The method of  claim 6 , further comprising:
 in response to determining the unlicensed frequency channel is available based on the sensing, communicating second data via the unlicensed frequency channel.   
     
     
         8 . The method of  claim 6 , wherein sensing signals on the unlicensed frequency channel comprises sensing one or more signals a plurality of times. 
     
     
         9 . The method of  claim 1 , further comprising:
 communicating a reference signal via the unlicensed frequency channel during the first subinterval.   
     
     
         10 . A method comprising:
 detecting, at a mobile device, a signal on unlicensed frequency channel:   receiving first data via a licensed frequency channel;   receiving second data via an unlicensed frequency channel; and   multiplexing the first and second data to form a first frame of data.   
     
     
         11 . The method of  claim 10 , further comprising:
 synchronizing receipt of the first data based on a synchronization signal received via the unlicensed frequency channel.   
     
     
         12 . A cellular base station, comprising:
 a frame control module to:
 in response to determining that an unlicensed frequency channel is available for data transmission:
 generate a first frame of data including a first portion of first data targeted to user equipment; 
 communicate the first frame of data via a licensed frequency channel for a first interval; 
 communicate a second portion of the first data of via the unlicensed frequency channel for a first subinterval of the first interval; and 
 subsequently suspending communication of data via the unlicensed frequency channel for a blank subinterval of the first interval. 
 
   
     
     
         13 . The cellular base station of  claim 12 , wherein the frame control module is to:
 in response to determining at the base station that the unlicensed frequency channel is not available, communicate the first frame of data via the licensed frequency channel for the first interval and suspending communication of data via the unlicensed frequency channel during the first interval.   
     
     
         14 . The cellular base station of  claim 12 , wherein the frame control module is to:
 set a length of the blank subinterval in response to detecting a signal on the unlicensed frequency channel.   
     
     
         15 . The cellular base station of  claim 14 , wherein the frame control module is to set the length of the blank subinterval by increasing the length of the blank subinterval in response to not detecting a signal on the unlicensed frequency channel. 
     
     
         16 . The cellular base station of  claim 15 , wherein the frame control module is to set the length of the blank subinterval by decreasing the length of the blank subinterval in response to detecting a signal on the unlicensed frequency channel. 
     
     
         17 . The cellular base station of  claim 12 , further comprising:
 a signal detector to, after the frame control module has communicated the first frame of data, sense one or more signals on the unlicensed frequency channel to determine an availability of the unlicensed frequency channel.   
     
     
         18 . The cellular base station of  claim 17 , wherein the frame control module is to:
 in response to the signal detector determining the unlicensed frequency channel is available based on the sensing, communicate second data via the unlicensed frequency channel.   
     
     
         19 . The cellular base station of  claim 17 , wherein the signal detector is to sense one or more signals on the unlicensed frequency channel a plurality of times. 
     
     
         20 . The cellular base station of  claim 12 , wherein the frame control module is to:
 communicate a synchronization signal via the unlicensed frequency channel during the first subinterval.